KLK3 and posterior cortical atrophy: The converging findings from the above studies are that: 1) the PSA−/lo PCa cells pre-exist in untreated HPCa; 2) PSA−/lo PCa cells become enriched in patient CRPC and AI xenograft models; and 3) PSA−/lo PCa cells respond to antiandrogens and several other therapeutics differently than the PSA+ PCa cells.